More info: SpiderOak presents itself as the secure public cloud storage option. Boasting a "zero-knowledge" policy, SpiderOak's program does not store passwords of customers, and all customer data is encrypted both in transmission and while in storage, using salted hashes and a combination of 2048-bit RSA and 256-bit AES encryption. For developers of the crowd, the company has also begun open sourcing some of the code used to create the product. SpiderOak offers personal, business and partner/reseller versions of its cloud service.
Free cloud storage: 5GB
Extra storage: 30GB, $4.99/month or $49.99/year; 60GB, $9.99/month or $99.99/year; 500GB, $39.99/month or $399.99/year. Business account offers 100GB for three users for $29.99/month or $299.99/year.
More info: Up to 32GB of free additional storage available if you recommend others that sign up for the service. SugarSync has mobile apps available on iOS, Android, BlackBerry, Symbian and WinMobile platforms.
Free cloud storage: Up to 10GB
Extra storage: Symform offers by far the largest amount of potentially free storage, but there's a catch. Its public cloud uses storage space donated by users, meaning other customers' encrypted data will be stored on your system when you contribute to the Symform cloud. The amount of storage each user gets is based on how much storage they contribute back to the Symform public cloud network. So, for example, if you contribute 2TB of storage, you can get 1TB of storage for free. Common use cases for this is around disaster recovery and backup. Customers can pay for the storage instead of contributing back excess storage space as well. Symform encrypts files using 256-bit AES, then divides files stored in the cloud into 64 blocks which are distributed throughout the Symform cloud network so that no one single user has access to a customer's complete set of encrypted data.
MORE SYMFORM: Symform has a public cloud without a data center
Free cloud storage: 2GB
Extra storage: 50GB, $15/month for personal edition.
More info: Syncplicity is owned by EMC. Pricing for business edition, which includes central access controls, start at $45/month with tiered pricing for up to unlimited storage. No file size limit or number of files. AES 256-bit encryption is used in transmission and at rest.